Angular rate measurement systems are used in many situations where it is useful to measure and determine a rate of rotation. For example, an angular rate measurement system may be useful for determining the rate of rotation of a vehicle, such as an airplane, truck, or car for purposes of determining the direction in which the vehicle is heading. Or, an angular rate measurement system may be useful for determining the rate of rotation of a cell phone which is being carried by such a vehicle. Such angular rate information may be used in a vehicle stability control system, navigation system, or elsewhere. For some angular rate measurement systems, the ability to accurately determine the angular rate is very important.
Many applications will use angular rate information in order to find a heading. For example, many military applications use an angular rate measurement system to find a heading (e.g. North), and that heading may then be used to control a missile or drone. If the heading is not accurately determined, such military vehicles may not arrive at the desired destination, which may result in unwanted and serious consequences.
Sensor bias errors, which are sometimes referred to as “offset errors”, are one type of error that can lead to a reduction in accuracy, particularly because sensor bias errors can accumulate and grow as signals derived from the angular rate information are processed, and thereby result in erroneous determinations. In order to provide accurate information, it is important to minimize or eliminate these bias errors (a.k.a. offset errors) so that the measurement system can be relied upon, for example, to find the heading of a vehicle to within a fraction of a degree.